The field of the present invention relates generally to inspection probes, and more specifically, to a method of integrating an inspection probe for use in measuring a machine component.
Prior to being placed in service, at least some known rotor blades or other components are measured using measurement probes to ensure that that the blade has the proper dimensions for use in a turbine engine. Often, such blades are inspected via a non-destructive inspection technique to ensure that each blade does not include internal defects and/or surface cracks that may not be visible to the naked eye. Additionally, it is important to measure both the external and internal geometry of the blade.
Coordinate measuring devices, such as coordinate measuring machines (CMMs), have been used for high accuracy, external dimensional measurement. Nondestructive examination (NDE) sensors including ultrasound (UT) sensors, eddy current (EC) sensors, etc., have been used separately to determine a thickness, internal defects, or surface condition measurements. With known systems, the two types of measurements are generally done separately. In some other applications, the NDE data was scanned along the tool path generated based on a normal CAD model, but have not been linked to nominal CAD model and/or the actual dimensions measured from CMM.
Known methods for measuring a blade generally require two separate processes to inspect both the external/internal geometry, or internal/surface defects of the blade. First, at least some known blades are inspected using computed tomography (CT) and/or ultrasound (UT) to inspect the internal geometry or defects of the blade. An eddy current (EC) sensor is typically used for identifying surface or near surface defects. A coordinate measuring machine (CMM) probe or a laser scanner on a CMM is then used to inspect the external geometry of the blade and for external dimensional measurement. Accordingly, a significant amount of time may be required to complete the setup and inspection process for each individual process of CT, CMM, EC, and/or UT. Moreover, automated UT/EC inspection currently requires a motion control system and, therefore, requires a pre-inspection process or a CAD model to program the system to accurately follow the contour of the blade.
Accordingly, such known inspection methods are generally time-consuming, not suitable for in-situ inspection, and/or expensive. Further, in at least some known inspection systems, the NDE measurement (such as EC) data is not directly linked to the geometry information. For example, if a surface crack is detected by an EC sensor, the location of the defect on the component is not associated to the geometry of the component being inspected. The location of the defects may be critical for deciding the health of a component. For example, if a crack is in a critical region, the component may not be reparable. In addition, the EC probe needs to be maintained in tight contact against the surface contour to ensure that the distance between the EC sensor and the component surface to be inspected is maintained substantially constant to avoid noise. The dimensional information acquired through CMM can be used to guide position EC probe normally and tightly to the contour of the component. For CMM, complicated blade geometry, such as a component having a deep, narrow opening or cavity, generally requires complicated setups and/or bending of the CMM probes to measure the cavity geometry.